332 Transactions. — Zoology. 



EXPLANATION OF PLATES XXIV.-XXX. 



Plate XXIV. 



Leptoclinum nii'euvi. 



Fig. 1. Part of a section of colony, showing the arrangement of spicules, 



&c. Enlarged about 2G diameters. 

 Fig. 2. Part of a section decalcified in hydrochloric acid, showing cloacal 



canals communicating with large ventral cavity. Enlarged 



26 diameters. 

 Fig. 4. Buccal tentacles seen from beneath in cross-section. Zeiss 



obj. C, camera. 

 Fig. 5. Branchial aperture from above. Z. C, camera. 

 Fig. 6. Test-cells from decalcified section. Z. E, camera. 

 Fig. 7. Curvature of alimentary canal, seen in cross-section from above. 



Z. A, camera. Slightly enlarged. 

 Fig. 8. Group of calcareous spicules. Z. E, camera. 

 Fig. 9. Detail of branchial sac and dorsal languets. Z. E, camera. 

 Fig. 10. Zooid, showing arrangement of parts and method of gemmation, 



with reproductive bodies. Z. A, camera. 



Plate XXV. 

 Leptoclinum cUnsuvi. 



Fig. 1. Portion of a decalcified section, showing common cloacal open- 

 ing. Enlarged 26 diameters. 



Fig. 2. Portion of a section in the natural state, showing the distribu- 

 tion of spicules. Enlarged 26 diameters. 



Fig. 3. Test decalcified and strongly magnified, showing details of 

 structure. Zeiss E, camera. 



Fig. 4. Branchial aperture from above. Z. C, camera. 



Fig. 5. Branchial siphon, with buccal tentacles. Z. C, camera. 



Fig. 6. Spicules from test. Z. E, camera. 



Fig. 7. Zooid, with testis and ovum and vascular appendage (test-vessel) 

 in situ. Z. A, camera. 



Pig. 8. Reproductive bodies. Z. C, camera. 



Fig. 9. Portion of test (decalcified), with ovum and developing embryo. 

 Z. A, camera. 



Fig. 10. Tailed larva (abnormal), with 4 adhering papilliE. Z. A, 

 camera. 



Fig. 11. Normal larva (3 papillae) Z. A, camera. 



Plate XXVI. 

 Leptoclinum tuberatum. 



Fig. 1. Part section of colony showing arrangement of spicules and 



passages in the test. Enlarged 26 diameters. 

 Part section of colony decalcified, showing vascular appendages, 



&c. Enlarged 26 diameters. 

 Surface layer of test, showing branchial apertures, position of 



zooids, spicules, &c. Zeiss A, camera. 

 Group of spicules. Z. E, camera. 

 Side view of branchial siphon, showing descending lobes of the 



test, tentacles, etc. Z. C, camera. 

 Detail illustrating branchial sac and dorsal languets. Z. E, 



camera. 

 Complete view of a single zooid showing the arrangement of 



parts and method of gemmation. Z. A, camera. 

 Tailed larva, with sense-organs and adhering papilla?. Z. A, 



camera. 



